Numerical Analysis of Subgrade Behavior under a Dynamic Maglev Train Load

Abstract

Medium-low-speed maglevs are increasingly used in the urban rail transit industry because of their advantages, such as low noise and low energy consumption. In this study, a finite element analysis of the responses of the subgrade that supports a medium-low-speed maglev structure under a dynamic maglev load is presented. First, the finite element analysis considers a low-lying structure with different elastic moduli. Then, the attenuation laws of the dynamic stress and dynamic deformation for different depth ranges of the subgrade under the rail beam are analyzed. In addition, the magnitude of the influence of the dynamic load is clarified. The results lead to a recommendation of a base bed thickness of 1.5 m, graded gravel or group A filler as the surface layer of filler, and gravel soil as the bottom layer. This study provides theoretical support for the construction design of a subgrade structure under the rail beam of a low-lying maglev line.

Physical modeling of long-term dynamic characteristics of the subgrade for medium–low-speed maglevs

“…In a previous study [2,18], the numerical simulation results show that the position of the peak value of the dynamic stress is near the edge of the base plate. Therefore, in this study, earth pressure cells and accelerometers are also installed at the edge of the base plate.…”

“…It is pretty suitable for urban rail transportation. A medium-low-speed (MLS) maglev has a running speed of less than 160 km/h, and future research studies on MLS maglev transportation will aim to achieve an operating speed of 200 km/h [2]. At present, many test lines for MLS maglev trains have been built in various countries, including Japan's Eastern Hills Line [3], South Korea's Incheon Airport Line [4], the MLS test line of the German Company Borg [5], the Changsha test line of the National University of Defense Technology [6], the Qingchengshan test line of Southwest Jiaotong University [7], the Shanghai Lingang test line of Tongji University [8], the CRRC Tangshan test line [9], the Zhuzhou test line [10], and the Beijing S1 test line [11].…”

“…Since the lack of technical standards of the MLS maglev subgrade, few studies have assessed the MLS maglev subgrade. Liu [18] and Wang et al [2] studied the dynamic characteristics of the MLS maglev subgrade through theoretical analyses and numerical simulations. They optimized the subgrade structure of an MLS maglev with the thickness of the upper roadbed being 0.3 m, the fill being graded gravel or group A-fill, and the compaction coefficient K ≥ 0.95.…”